COCKROACHES IN THE UK: DESIGNING BUILDINGS TO REDUCE THE RISK OF INFESTATION

Abstract:
Cockroaches require relatively warm conditions and in the UK are mainly confined to buildings. These insects are capable of carrying food-poisoning bacteria and causing allergies. To avoid these adverse health effects the risk of cockroach infestations in buildings needs to be minimised. This paper reports on a survey of the findings of environmental health officers in England and Wales when assessing the scale of cockroach infestation and subsequently considers the effects of building design on minimising spread. Over 80% of local authorities who responded reported cockroaches; infestation was more common in metropolitan and urban areas than in rural authorities. Infestations were reported to be most serious in multi-occupancy dwellings such as tower blocks and low rise flats. More than a third of the authorities associated cockroach infestations in these buildings with ducted servicesand rubbish chutes and considered both contributed towards difficulties in achieving control. In a subsequent study, detailed examination of flats in an infested block found discarded food and evidence of cockroaches in 'service cupboards' which provided access to electricity cables and water pipes. These 'service cupboards' ran vertically the full height of the building and gaps around pipes passing through each floor were sufficiently large to allow cockroaches to move vertically between floors. In these flats, cockroaches could also spread horizontally using the space between the floor and ceiling. Droppings within these voids confirmed their use by cockroaches. Complete exclusion of cockroaches, from dwel1ings is rarely practical. However this paper suggests measures which can significantly reduce risks of spread, such as sealing or reducing voids whith provide harbourage and distribution channels within and between dwellings. It recommends all ducts should be sealed where services pass through walls, ceilings and floors; essential voids should have access hatches and high standards of hygiene should be maintained within ducts. These measures are best achieved and most likely to succeed if implemented during the initial construction phase.